This invention relates to vacuum-breaking valves for pressurized fluid lines.
Vacuum-breaking valves of the general type described herein are used widely in fluid supply systems to prevent back siphoning, or flow reversal whenever an operational variant causes a vacuum to be produced in the supply system. This is of particular importance in the case of Municpal Water Supply Systems which are subject to pressure variation. If the pressure in the supply system drops below atmospheric pressure, even momentarily, contaminating materials present in the house delivery system may be drawn into the main line with obviously disadvantageous results.
Such a situation may occur, for example, when water is supplied to mortuaries, hospitals, laboratories, laundries, chemical processing installations and the like. All of these may introduce serious sources of contamination into possible communication with the domestic tap water. Examples of such sources are the formaldehyde wash waters used for disinfecting kidney machines; mortuary fluids and wash waters; bacteriologically contaminated laboratory solutions; poisonous chemical solutions, etc.
No problem exists as long as normal pressure is maintained on the house line supplying water under pressure to the installation. However, in the event of failure of the pressurized water source, disconnecting the pressurized line for purposes of installation or repair or other occurrences, circumstances frequently arise wherein the pressure in the pressurized house line is reduced sharply. A vacuum may even be created. In such occurrences, contaminating fluids may be drawn into the system and subsequently discharged through the domestic tap.
It is the general purpose of the present invention to provide a vacuum-breaking valve for pressurized fluid lines which provides a solution to the above described problem.
It is a further object of the present invention to provide a vacuum-breaking valve which is simple in construction, efficient in operation, easily installed, adaptable for use in a wide variety of plumbing situations; and reliable and trouble-free in operation.
Broadly stated, the vacuum-breaking valve of my invention is adapted for use in a pressurized fluid line delivering liquid to an outlet. It includes a conduit adapted for tapping into the line upstream of the outlet.
A bell-shaped housing connects to the conduit and is mounted thereon, in inverted position. The interior of the housing has an annular, outwardly facing shoulder which provides a seat for check valve means dimensioned for reception in the housing.
A retainer is positioned in the housing for releasably retaining the check valve therein. As long as pressure is maintained in the fluid line, the check valve remains closed. However, if there is a serious drop in pressure in the line, the check valve opens, admitting air, breaking the vacuum, and preventing back-flow of contaminated materials into the system .